Circuit maker and breaker



Oct. 6, 1942.

4. s. CLARK CIRCUIT MAKER AND BREAKER Filed Dec. 13, 1939 4 Sheets-Sheet l INVENTOR. C2 en.

Oct. 6, 1942. J, & A K 2,298,108

CIRCUIT MAKER AND BREAKER Filed Dec. 15, 1939 4 Sheets-Sheet 3 INVENTOR.

Jss n-r 6. (2 Ayes.

0d. 6, 1942. J 5 CLARK 2,298,108

CIRCUIT MAKER AND BREAKER Filed Dec. 15, 1939 4 Sheets-Sheet 4 INVENTOR. JasEPH 6. C2 5.9K,

Patented Oct. 6, 1942 CIRCUIT MAKER AND BREAKER Joseph S. Clark, San Francisco, Calif., assignor of sixty per cent to Alferd A. Lauppe, Detroit, Mich., and twenty per cent to James F. White,

Amarillo, Tex.

Application December 13, 1939, Serial No. 308,921

8 Claims.

My invention pertains to ignition systems for internal combustion engines and more particularly to improved contacting means for closing and opening the primary circuit of an ignition system.

It is an object of my invention to provide circuit making and breaking means of improved reliability and durability for controlling the pri mary circuit of an ignition system in accordance with the operations of the engine to supply high tension impulses to the spark plugs of the engine in properly timed relation and at a suit able high tension at all engine speeds.

It is also an object of my invention to provide an improved circuit maker and breaker for ignition systems which will maintain the proper timing relation for all conditions of wear and which will be simple and rugged in construction and simple to install.

It is a further object of my invention to provide such an improved ignition circuit maker and breaker in an improved ignition distributor assembly for internal combustion engines.

Another object of my invention is to provide such an improved ignition distributor assembly including an improved spark advancing mechanism for automatically advancing and retarding the spark in accordance with the varying speeds of operation of the engine.

Further objects and advantages are within the scope of my invention, such as relate to the arrangement, operation and function of the related elements of the apparatus, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features, as will be apparent from a consideration of the specification in conjunction with the drawings disclosing specific embodiments of my invention, in which similar reference characters have been applied to corresponding parts throughout, and in which:

Fig. 1 is a side elevational view showing an ignition distributor assembly embodying my invention;

Fig. 2 is an enlarged sectional view taken on line 22 thereof and partially broken away to show the internal construction thereof;

Figs. 3 and 4 are cross-sectional views taken on lines 33 and 44 respectively, as shown in Fig. 2;

Fig. 5 is a plan View looking down into the distributor with the high tension cap and the distributor contact arm removed;

Fig. 6 is an exploded perspective view showing the component parts of my distributor disposed in disassembled relation;

Fig. 7 is a cross-sectional view taken on line I'| shown in Fig. 2;

Fig. 8 is a schematic View diagrammatically representing my improved circuit making and breaking arrangement connected into an ignition system;

Fig. 9 is a vertical sectional view showing a modified embodiment of my distributor comprising an automatic spark adjusting mechanism;

Fig. 10 is an enlarged detail view of a portion of the stationary contact ring showing the contact face of one of the stationary contacts which is so shaped that the timing of the spark is varied by raising or lowering the rotating contact balls;

Fig. 11 is a sectional view on line |0l0 of Fig. 9, and

Fig. 12 is a plan view, partially diagrammatic, showing a modified contact arrangement.

Referring more particularly to Figs. 1 and 2 of the drawings, I have shown my improved ignition circuit making and breaking device conveniently assembled in the conventional ignition distributor comprising the well-known open top distributor housing I of circular cross-section supported by a neck 3 extending down from the closed lower end of the housing to the crank case 5 of an internal combustion engine (not shown). The open upper end of such a distributor housing is usually closed by a high tension cap 1 made of suitable electrical insulating material with an annular rib 9 projecting snugly into the distributor housing I on which the cap is secured by spring clips I l to hold the cap firmly for obstructing the entrance of foreign matter. As will be understood, the engaging portions of the high tension cap and the distributor housing usually have suitable interfitting portions to insure a proper angular position of the cap at all times so that the high tension contacts in the cap (not shown) which are associated with the respective high tension cable sockets [3 in the cap will always be placed and maintained in a proper angular position thereon for proper cooperation with the high tension distributor contact arm l5 as it rotates.

Extending in suitably journalled relation through the neck 3 of the distributor, is the usual distributor shaft 11, which at the lower end may be driven from the cam shaft (not shown), which runs at half the speed of rotation of the crank shaft, or it may be driven from the crank shaft of the engine by suitable gears (not shown) at a speed equal to half of the speed of rotation of the crank shaft in the usual manner. The upper end of the distributor shaft I1 extending into the distributor housing I is of a reduced diameter and has a transverse slot :9 to receive a pin 2| extending transversely through the midportion of a tubular sleeve 23 which fits down upon and extends above the upper end of the shaft I1. A distributor arm cap 25 of electrical insulation material fits upon the upper end of the sleeve 23 and rotatably carries the high tensiondistributor arm in the usual manner. The

upper end of the tubular sleeve 23 has a slot 21 therein for receiving an inner projection 29 from the distributor arm cap toinsure the proper angular position of the high tension distributor arm 15 on the distributor shaft I! at all times.

In accordance with my invention I provide a circular base plate or disk 3i having a centralaperture passing freely over the distributor shaft I? so that the base plate fits snugly down upon the closed bottom of' the distributor housing I. The base plate 3! is suitably apertured to receive the lower ends of two stud shafts equally spaced on opposite sides, of the. distributor shaft IT. The intermediate portion of each stud shaft 35 has a shoulder 37 of a larger diameter engaging a spur gear 39 journalled upon the upper end of each stud shaft. The gears 39 are thereby supported and journalled on stationary stud shafts 35 in spaced relation above the base plate or disk 35. A drive gear at is secured firmly upon the distributor shaft ll, as by a pin 33 passing transversely through the up-turned hub it of the gear. The drive gear ii is mounted slightly spaced above the upper surface of the base plate 3! and meshes with the innermost or adjacent teeth of the two spur gears 39 which are driven therefrom.

To carry circuit controlling. contacts I provide a circular contact rotor ii; of annular conformationhaving an internal diameter sufficient to pass freely around the hub of the drive gear. The external diameter of the contact rotor is slightly less than the internal diameter of the distributor housing i in order that the contact rotor may rotate freely therein. This contact rotor :35 maybe made of any suitable material, but I prefer to make it of. electrical insulation material such as fiber board, Bakelite orthe like to facilitate insulation. An internal spur gear 65. is secured to theunder side of the rotor 45, as by screws ll passing therethrough, and having the internal gear teeth thereof meshing with the outwardly turned teeth of the spur gears 39 for driving the contactor rotor ts from the gear M on the distributor shaft ll, as may be seen more clearly in Fig. '7.

Mounted upon the upper side of the contactor rotor 65 and extending radially on opposite sides of the distributor shaft ll are two contact guide sleeves or contact sockets 5| which are secured thereon by means of screws 53 passing up through the rotor into suitably threaded apertures in the lower sides of these sleeves. Each contact guide sleeve 5! is closed at one end and open at the other end and these are mounted with the open ends opening outwardly in diametrically aligned and opposed relation. Contactv uide sleeves iii are of any suitable metal and the outer open ends are spaced in substantially from the outer wall of the distributor housing I, as may be seen in Figs. 2 and 5. A flat metallic band or ring 55 is provided which passes over the. upper sides of the two opposed gui e sleeves;

The

metallic ring 55 is secured rigidly to the opposed guide sleeves iii in any suitable manner, as by soldering or welding, and serves to secure these rigidly in properly aligned relation while also providing a low resistance electrically conductive connection therebetween.

Slidably disposed in the outer end of each contact guide sleeve 5i is a contact ball 5? which is continuously biased outwardly by a ball race member 59 therein and a biasing spring 6! compressed between the outer head portion of the ball race member and the closed under end of the contact guide socket ti. The ball contact 51 may be a steel ball bearing and, as shown in Fig. 4, the adjacent end of the ball race member 59 is provided with a depression 53 having a smooth concave surface of a greater curvature than the ball contact to permit the ball to turn and roll freely to all positions in operation. Any change in. engine speed also causes a corresponding change in the balls orbit.

A stationary contact ring 65 is provided having an. outer diameter suitable for fitting into the distributor housing 5 and resting upon a shoulder 6? therein. The inner diameter of the contact ring 5'5 is such that the ring ts down into the annular space between the outer open ends of. the contact guide sockets 5i and the distributor housing so that the outwardly pressedcontact balls 5? run smoothly around the inner surface of the stationary ring as the contactor rotor 45' turns therein. The stationary contact ring. 65" is made of any suitable electrical insulation material having sufiicient strength and rigidity and being resistant to oil, such as fiber, Bakelite or the like. As shown in Figs. 4. and 6, the contact ring carries a plurality of electrical contacts 69 of copper, beryllium, or other electrical conductive metal, which are equally spaced around the ring and are exposed flush with the inner surface of the ring. For a six cylinder engine and with the contactor rotor 45 turning at one fourth crank shaft speed, as in the present embodiment, I preferably provide a total of twelve such contacts exposed through the inner surface-of the stationary contact ring 65'.

As may be seen in Figs. 2, 4 and 6, interconnecting bus bars H of arcuate shapes are embedded in an annular groove 73 which extends circumferentially around in the outer surface of the contact ring. The bus bars H are connected to, or are made integral with; the portions of the. stationary contacts 59 which extend outwardly through the ring. These are arranged in such a manner as to connect the contacts. 69

together in two groups of six contacts each, as may be seen more clearly in Fig. 4, and which is diagrammatically represented in Fig. 8. The outer surfaces of the bus bars H are slightly inset in the stationary contact ring- 65: so that electrical conductive contact with the distributor" shell I is not possible and a coating of shellac of suitable electrical insulating varnish may be applied thereto.

Although the six contacts of each group are conductively connected together through an arouate bus bar H connected or integral therewith.

and the two rotating ball contacts 51 are conductively interconnected, the primary circuit of the ignition system is broken simultaneously at two points adjacent the two balls thus providing a quick break, minimizing arcing, and widely distributing the heat of the arc. The sweep of the ball contacts 51 over the face of each stationary contact is the period of dwell during which the current in the primary circuit must build up to energize the ignition coil. The length of the time interval of the period of dwell in my system is determined by the circumferential dimension of each stationary contact 69 which is properly selected for this purpose and does not vary with wear and is not changed by external adjustments.

In my preferred arrangement, as shown, for a six cylinder engine a total of twelve stationary contacts are provided divided into two groups of six contacts each, and with the rotor turning only half as fast as shaft I! or one-fourth as fast as the engine, six D. C. impulses pass through the contact balls in one direction and then the direction of current flow through the balls is reversed as the two contact balls 51 each moves adjacent the other group of stationary contacts. However, it is to be understood that rotor 45 could be keyed directly to the shaft I7 and then a total of stationary contacts would be sufficient with three in each group and the D. C. through the rotating contact balls 51 would be in reverse direction every time three sparks were produced.

To adjustably turn the stationary contact ring 65, sufficiently for adjustably advancing or retarding the spark, an L-shaped lever is secured thereto by inserting one leg thereof into a suitable aperture in a radial groove H in the upper side of the ring so that the leg of the lever extends radially outward from the groove and projects out through a slot 19 in the side of the distributor housing I. By means of the outwardly projecting end of the lever 15, the position of the contact ring 85 therein may be shifted through an angle suflicient to advance or retard the spark properly in accordance with all operating conditions of the engine. This may be accomplished either manuall or automatically in any usual manner as will be readily understood.

A spring retainer ring 8! is provided which is compressed and inserted into the distributor housing I above the contact ring 65 to limit its upward movement as caused by vibration and the like. Screws S3 threadably pass through the side wall of housing I to hold the ring. The distributor housing I may be filled with a suitable oil or grease.

A conductor 85 is electrically connected to one of the arcuate bus bars H, and extends therefrom to one terminal of the usual condenser C having a lug 81 which is secured upon the upper side of the contact ring as by a suitable screw 89, which connects to the other bus bar H. A conductor 9'! may connect from conductor 85 and extend from the distributor housing in the usual manner for connecting the improved circuit maker and breaker into the primary circuit of any ignition to be controlled thereby, with the usual condenser C connected in shunt therewith where it serves to intensify the high tension spark delivered in addition to decreasing arcing in the primary circuit.

In Fig. 8 my improved circuit making and breaking contactor device is diagrammatically represented in operative connection in one conventional form of ignition system in which it may be advantageously utilized. In the diagram SP are the spark plugs and I is any conventional ignition coil comprising a primary winding P and a secondary winding S. B represents the usual storage battery of an automobile. One terminal of the battery B may be grounded by a conductor 93 to the frame of the car and one side of each spark plug SP is directly grounded in a wellknown manner. One bus bar H of my contactor is grounded by a conductor 85 or this ground may be connected from the conductor lug 81 which is one terminal of the condenser, as will be understood. A conductor 97 connects from the other arcuate bus bar H and the other terminal of condenser C to one terminal of primary winding P of the ignition coil I. The other end of primary winding P is connected to one end of the secondary winding S and a conductor 93 connects to the usual ignition switch it] on the instrument board from which a conductor I03 connects to the positive or ungrounded terminal of the battery B. The other end of the secondary winding S is connected by a conductor I85 to the rotary high tension distributor arm 15 which is rotatably carried on the upper end of the dist ibutor shaft i! to be carried selectively adjacent the high tension contacts in the distributor cap, as previously described.

In accordance with my invention, each arcuate bus par ii has a plurality of connected contacts 89 which project inwardly in spaced relation to define a circular path, with the group of contacts from each bar T! extending about half around the circle. The contacts 69 are disposed in 0pposed pairs and as the rotor 45 is driven from the distributor shaft ll, the conductively interconnected contact balls 5''! pass smoothly over the cont cts and interrn" tently establish a bridgin connection between the two groups of con tacts, thus energizing and deenergizing the primary winding P of the ignition coil in proper phase relation to the nstantaneous position of the respective pistons of an engine for properly supplying high tension impulses from the secondary winding 8 through cables to? to the spark plug SP of the proper cylinder, as selected by the distributor arm i5. As the two contact balls 51 roll smoothly over the stationary contacts 69 the primary circuit is made and broken at two points with a firmly established low resistance contact even at the highest speeds. A minimum of arcing of burning of the contact balls of the stationary contacts occurs, so much so that it may be said to be negligible. The contactor is of long life and does not require frequent adjustment and replacement, and the accuracy of timing of the distributor is inherent in its construction and is not adversely effected by any wear that might be present even after a long period of operation. By means of the adjusting lever shown in Figs. 2, i and 5, the contact ring may be adjustably shifted sufficiently for properly timing the spark. Also if desired any suitable well known mechanism may be connected with the contact ring 55 for automatically adjusting the angular position at all times in accordance with the speed or other operatin conditions of the engine, as will be readily understood.

In Figs. 9, l0 and 11 I have illustratively disclosed a different embodiment of my ignition distributor which includes a spark advancing and retarding mechanism for automatically adjusting the timing of the spark in accordance with the speed of operation of the engine. In this embodi ment of my improved distributor many elemerits may be the same as the corresponding elements in the previously described embodiment, and to facilitate understanding the similarity and the difference between these two embodiments, the same reference characters have been applied to parts which may be the same. Referring es pecially to Fig. 9, it will be seen that my automatic distributor similarly embodies the usual distributor shaft l'i journalled in the neck 3 of a distributor housing I and rotatably carrying a high tension distributor arm E3 on an insulating support 25 on the upper end. Also the open upper end of the distributor housing l receives a distributor cap 7 of insulation for closing the distri butor housing and supporting the high tension contacts adjacent the distributor arm l5, with spark plug cables extending therefrom.

In my automatic distributor, a stationary contact ring 65 is also similarly inserted into the distributor housing I except that it sets up on a shoulder I! l on the inside wall of the distributor housing I which is higher up from the bottom and closer to the open end ofthe housing. A screw Ht may pass through a slot H2 in the side of the distributor housing 1 for securing the contact ring 55 in a properly selected position. The stationary contact ring is made of any electrical insulation material having suitable strength and rigidity and resistance to oil and grease, as in the previous embodiment.

Also a plurality of electrical contacts H3 are provided which, though of a special shape, are similarly mounted in and spaced around the inner surface of the ring with the faces of the contacts flush with the inner surface of the ring to form a smooth contiguous surface of revolution therewith, and these contacts are joined together in two conductively connected groups each extending around one half of the circular contact path through two arcuate bus bars H embedded in the insulating ring.

In my automatic distributor the stationary contacts are also bridged together in diametrically opposed pairs by contact balls 5'! carried in guide sleeves 5!, urged outwardly by springs 65 and ball races 59, supported upon an insulating rotor 45 and electrically interconnected through a ring 55' joined to the upper sides of the guide sleeves as in the previous embodiment.

Fig. is an enlarged detail view showing a small section of the inside surface of the contact ring 65 sufficiently to show the contact face of one of the contacts I t3 illustrating the special shape of contact face provided. Arrows are provided to show the direction of travel of the ball contact 5'! in sweeping over the face of one of the contacts l [3 and to illustrate that the contact ball 57, shown in dotted lines, traverses the face of the contact at different positions for different speeds, which is accomplished in a manner to be described. The arrows as numbered (1), (2) and (3) show that different contact paths are followed at different speeds such as at (1) for av high speed; at (2) for a medium speed and at (3) for a slow speed, respectively.

More specifically the face of the contact member H3, as shown in Fig. 10, is a figure flush with the ring at top and bottom and bounded on the sides by two lines extending from the upper side of the ring to the lower side and spreading apart so that the circumferential path of contact is longer across the lower portion of the contact than it is across the upper portion.

lhelength of the contact path traversed by the ball contact determines the period of dwell. or time during which the current grows in the primary winding of the ignition coil to build up a field flux of the intensity necessary to induce a hot spark from the secondary winding. By making the contact face of a width tapering properly from narrow at the top (for sloW speed) to wider at the bottom, and by causing the contact balls to traverse the narrow part at low speeds and the wide part at high speeds, a constant dwell period is provided to produce a hot spark at all speeds.

It will also be seen that position of the contact face I i3- is such that at the top it inclines or leans counterclockwise or backwards and away from the approaching contact ball; and, because the timing of the spark is controlled by the position of the lagging or under side of the leaning contact face, it will be apparent that this position or shape of the contact face causes the timing of the spark to be automatically regulated when combined with means for lifting and lowering the contact balls accordingly as the engine runs slow or fast.

Also this spark shifting or timing arrangement very conveniently lends itself to still further refinement by making the inclined sides of the con-- tact face a curved line, as shown, rather than a straight line, and by selecting the curvature as some function of the ignition and compression curves and any other factors which effect the proper timing of the engine. Also different shaped contact faces may in this manner be provided to suit the different operating characteristics of different internal combustion engines, or for engines operating under different conditions of altitude, temperature, or other conditions which may be permanent for certain classes of prime movers in certain or particular locations, fields of service, or the like.

For lowering or elevating the contact balls 5'! in accordance with the speed of operation, I provide a pair of inclined metallic cam surfaces Ill secured by screws M9 on an inclined portion of the bottom of the rotor 35. on opposite sides of the shaft H and inclining downwardly and toward the shaft. Adjacent the bottom of the distributor housing, I provide a weight disk l2! keyed to the shaft if as by a pin E23 and having a pair of pivot pins E25 rising from the upper face of the disk on opposite sides of the shaft. Pivoted upon the upper end of each pin l25 is a weight E2? of a generally arcuate shape for fitting around the shaft and havingv a heavier weight i29 adjacent the swinging end. Tension springs 53! of suitable strength are tensioned between eyelets I33 in the two pivoted weights for normally drawing the weights together toward the shaft if and resisting centrifugal action. On the upper face of each weight 425 is an upstanding cam surface 535 of suitable inclination for cooperating with the down-turned cams I H on the rotor 45, for lifting the rotor 65 at slow speeds and for lowering the rotor as the speeds increase.

For imparting rotation to the rotor 45 and maintaining it at a predetermined angular relaticn with reference to the weight disk 12! and the distributor shaft ll, drive pins l3! rise from the upper side of the disk and slide freely through apertures P89 in the rotor 45. Tension springs lei are stretched between eyelets I43 on the weight disk and the rotor 45 to insure that the rotor is smoothly drawn down as the speed of operation decreases.

With increasing speeds the weights [2! tend to open or spread apart and this lifts the rotor 45 and the contact balls 5'! to traverse the upper portion of the contact faces H3 to advance the spark, in the manner previously described. As the speed decreases the weights are drawn together by the springs, the rotor 45 is lowered and the contact balls 51 sweep over the wider portion of each contact face as indicated by arrow (3) in Fig. 10 and this retards or advances the timing of the spark in accordance with the speed and any special operating characteristics of the engine, while maintaining a constant dwell period for a hot spark at all speeds. The details of this operation have been fully discussed previously with reference to the special shape of the contact face as shown in Fig. 10, and will not be repeated. It is to be understood that the same principles may be advantageously realized even if the speed responsive mechanism were connected with the rotor in an alternative arrange- 1 ment for lifting the rotor with increasing speed and lowering the rotor for slower speeds as this would merely involve inverting the contact ring and contacts. Also the rotor may be driven in a clockwise direction rather than a counterclockwise direction and the principles of my invention equally well realized by reversing or inverting the contacts accordingly, as will be readily understood.

In Fig. 12, I have shown a modified arrangement of the stationary contacts comprising one group of stationary contacts 69 conductively or integrally joined through an arcuate bar H and the other contact is an arcuate bar presenting a single smooth contact face. It is to be understood that these stationary contactor members 69, H are ail mounted in an insulation 55 just as in the previously described embodiments. In this contact arrangement, the interruption of the primary circuit is caused as each contact ball 51 sweeps over the spaced contacts 69, at the left hand side as shown.

It is apparent that within the scope of the invention, modifications and different arrangements may be made other than herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

I claim:

1. A primary contactor for ignition distributors comprising, a plurality of stationary contacts arranged in equally spaced relation in diametrically opposed disposition around a circular path, electrical conductive means for connecting perinanently together as a conductive group all the contacts around half of the circular path, additional conductive means for connecting permanently together as a second conductive contact or group all the contacts of the other half of the circular path, rotatable contactor means arranged for sweeping around said circular path to bridge said stationary contacts in succession for intermittently making and breaking a circuit between the two conductive groups of contacts, and a distributor shaft disposed adjacent said contacts and adapted to be driven from the crank shaft of an engine in the usual manner.

2. A primary contactor for ignition distributors comprising, an even number of stationary contacts arranged in equally spaced relation in diametrically opposed pairs around a circular path, the number of said contacts being twice as great as' the number of spark plugs to be energized, insulation material disposed between said contacts to provide a smooth contiguous surface of revolution around said circular path, electrical conductive means for connecting permanently to gether as a conductive group all the contacts around half of the circular path, additional conductive means for connecting permanently together as a second conductive group all the contacts of the other half of the circular path, rotatable contactor means arranged for sweeping smoothly around said circular path to bridge respective pairs of said stationary contacts in succession for intermittently making and breaking a circuit between the two conductive groups of contacts, a distributor shaft disposed adjacent said contacts and adapted to be driven from the crank shaft of an engine at half crank shaft speed in the usual manner, and means driven from said shaft for rotating said contactor means at half the speed of rotation of said distributor shaft.

3. A primary contactor for ignition distributors comprising, an even number of stationary contacts arranged in equally spaced relation in diametrically opposed pairs around a circular path, insulation material disposed between said contacts to provide a smooth contiguous surface of revolution exposing said contacts around the inside of said circular path, electrical conductive means for connecting permanently together as a conductive group all the contacts around half of the circular path, additional conductive means for connecting permanently together as a second conductive group all the contacts of the other half of the circular path, a pair of ball contacts arranged for sweeping smoothly around the smooth inside surface of said circular path to bridge respective pairs of said stationary contacts in succession for intermittently making and breaking a circuit between the two conductive groups of contacts, means for biasing said ball contacts outwardly, electrically conductive means connecting between said balls, a distributor shaft disposed adjacent said contacts and adapted to be driven from the crank shaft of an engine in the usual manner, and means connecting said contactor means to be driven by said distributor shaft.

4. A primary contactor for ignition distributors comprising, an even number of stationary contacts arranged in equally spaced relation in diametrically opposed pairs around a circular path, insulation material disposed between said contacts to provide a smooth contiguous surface of revolution around said circular path, electrical conductive means for connecting permanently together as a conductive group all the contacts around half of the circular path, additional conductive means for connecting permanently together as a second conductive group all the contacts of the other half of the circular path, a pair of ball contacts, contact support means for supporting said ball contacts in spaced apart relation and conductively interconnected, said contact support means being movably arranged for sweeping said ball contacts around said circular path to bridge respective pairs of said stationary contacts in succession for intermittently making and breaking a circuit between the two conductive groups of contacts, and a distributor shaft adapted to be driven from the crank shaft of an engine in the usual manner.

5. A primary contactor for ignition distributors for siX cylinder internal combustion engines comprising, twelve stationary contacts arranged in equally spaced relation in diametrically opposed pairs around a circular path, insulation material dis osed betw en sa d contacts t provi e a sm th co i s surface o re olution around d i lar p h el tri a c nduc e m a s or c in perm e tly to et as a n d e oup e six con act arou d ha of t i c ar p t a d onal c nductive me ns for on ecti pe m ne tly to th r as a sec nd cone d ctive g p th ix con a s of th t er l of the circular path, rotatable contactor means arranged for sweeping around said circular path to bridge respective pairs of said stationary conta ts in uc e s on orci rm t en lv ma in a d break a ci u be ween the t o o u t ve groups of contacts, a distributor shaft disposed adjafient said contacts and adapted to be driven fr m the cr n haft o an e i n h usua man e A ma y on a ts to i i ion d st i u r comprising, a distributor housing, a distributor shaft therein adapted to be driven from the an shaft o an en ine n t e usual m n e a stationary contact ring of insulation material and of a suitable size for fitting into said hO l ing, Contacts exposed in equally spaced relation around the inner surface of said ring and disposed in diametrically opposed pairs, conductive means joining said contacts together in two sepae rate groups ea h g oup extendin su stantia y half around the ring, a rotor in said housing driven from said distributor shaft, and conductive bridging means carried by said rotor adjacent said contacts for engaging and disengaging said contacts in pairs of one contact in each group for intermittently completing a circuit between the two groups of contacts as said distributor shaft rotates.

A p i ary a tor fo i nition distri utors comprising, a distributor housing, a distributor shaft in said housing adapted to be driven irorn an internal combustion engine, a pair of arcuate contact members stationarily mounted in spaced apart insulated relation in said housing, contacts projecting inwardly in spaced apart relation from one of said arcuate members to define a surface of revolution with the inner face of the other arcuate member, a rotor in said housing driven from said distributor shaft, conductive bridging means carried by said rotor adjacent said contacts for intermittently completing an electrically conductive connection between said spaced contacts and the other arcuate member.

8. A primary contactor for ignition distributors comprising, a distributor housing, a distributor shaft in said housing adapted to be driven from an internal combustion engine, a pair of arcuate contact members stationarily mounted in spaced apart insulated relation in said housing, contacts projecting inwardly in spaced apart relation from one of said arcuate members to define a surface of revolution with the inner face of the other arcuate member, a stationary ring of insulation material in said housing for mounting said contacts in spaced insulated relation and for filling in between the inwardly spaced contacts to form a smooth surface of revolution therewith, a rotor in said housing driven from said distributor shaft, conductive bridging ball contacts carried by said rotor adjacent said contacts for intermittently completing an electrically conductive connection between said spaced contacts and the other arcuate member.

JOSEPH S. CLARK. 

